Blood glucose level – concept of insulin regulation
Let’s start the topic of blood glucose level–
Suppose you are driving a car and you find there is not sufficient air in one tyre. What will happen? It will be an imbalance; you may get an accident. So, it needs proper balance for driving.
Similarly, our body maintains homeostasis. In other words, your body maintains the proper temperature level, blood glucose level, blood pressure level, lymphatic system level, thyroid hormone level, and so on. If it disturbs, it may cause dysfunction of your body.
Currently, blood sugar level dysfunction incidence has been steadily increasing globally. High blood glucose level is a prevalent problem today, but low blood glucose may be fatal if we do not give much attention. These are significant public health problems.
If your blood glucose level is not within the limit or range, it will definitely be a problem. When your blood glucose levels get too high, you may face hyperglycemia or Diabetes Mellitus condition. If your blood glucose levels drop too, it may cause hypoglycemia.
Today we will understand how the blood glucose level manages by insulin and other hormones.
What is the blood glucose level? what blood glucose level is normal?
It represents the amount of sugar that present in your blood at any particular time. It could be normal, high, and low blood sugar level depending upon your lifestyle.
Let’s understand through a blood sugar chart.
Blood sugar range with and without diabetes –
Normal fasting blood sugar for a person without diabetes
70–99 mg/dl (3.9–5.5 mmol/L)
With diabetes (High blood sugar level)
80–130 mg/dl (4.4–7.2 mmol/L)
Blood sugar after a meal (postprandial blood sugar)
Normal – without diabetes
Less than 140 mg/dl (7.8 mmol/L)
Less than 180 mg/dl (10.0 mmol/L)
HbA1c (HbA1C is another diagnostic tool that tells the average blood glucose level of last 3 months)
Normal – without diabetes
Less than 5.7%
Less than 7.0%
How does blood glucose normally regulate in your body?
Islet of Langerhans is a cluster of cells that are scattered within the pancreas but more abundant at the tail of the pancreas. Around more than 1 million islets of Langerhans present in the pancreas.
The pancreas has two glands – exocrine gland and endocrine gland. Exocrine glands secrets digestive enzymes and bicarbonate which release into the duodenum. Whereas endocrine glands secret some peptide hormones from different cells.
α-cells or A cells
Surrounded β – cells
β – cells or B cells
Centre at Islet of Langerhans
C-peptide (equimolar amount),
Proinsulin (less amount)
δ-cells or D cells
Scattered throughout the Islet of Langerhans
Pp cells or F-cells
Scattered throughout the Islet of Langerhans
When your blood glucose level goes high, the pancreas secrets insulin by β – cells. Then insulin manages the increased blood glucose and sent them into the cell.
If your blood glucose level gets low. Then, the pancreas releases glucagon by α-cells of the pancreas, which helps in glycogenolysis. It provides glucose to cells by breaking down stored glucose from fat cells.
But somatostatin controls the overproduction of both hormones – Insulin and glucagon. It inhibits the secretion of insulin and glucagon as well. Somatostatin is also called universal inhibitors of a peptide hormone in pancreatic islets.
Pancreatic polypeptide is not much used in the regulation of blood glucose.
How does the insulin release?
Molecular pathway of Insulin release –
I have mentioned all the things stepwise. It will be easy to understand for you.
Firstly, we will have to understand about incretins. Incretins is a peptide hormone that presents in the epithelium layer of the intestine. Incretins are natural antidiabetic hormone. There are some essential functions of incretins –
1. GLP-1 (Glucagon-like Peptide-1) decrease glucagon and increase insulin hormone
2. GIP (Gastric Inhibitory peptide or Glucose-dependent Insulinotropic), which inhibits gastric emptying and increases satiety.
When you take food, which contains many nutrients like glucose, amino acids, fatty acid, and ketone. Among these nutrients, glucose stimulates the incretins that release and go into blood circulation.
Both glucose and incretins enter the blood circulation, then it stimulates β-cell of pancreatic islet.
Glucose binds on GLUT-2 transporter of β-cell of the pancreatic islet (GLUT-2 is a facilitated glucose transporter also present in Liver, Kidney, and Intestine)
Then the glucose is converted into Glucose-6-phosphate by Glucose kinase, and the Glycolysis cycle takes place.
It gives end product pyruvic acid, and then it goes into TCA (Krebs cycle)
It inhibits ATP sensitive K+ channel (means decrease the outflux of K+ ions)
Then Ca+2 channel open and increase intracellular Ca+2 ions
(means increase the influx of Ca+2 ions)
Eventually, exocytosis of store insulin and insulin release.
How does insulin manage glucose?
As you know, insulin is a manager of fuel molecules. When you eat food, your insulin starts to secrets and reaches into blood circulation.
Insulin is responsible for managing extracellular glucose stored in the liver, muscle, and adipose tissue in the form of glycogen.
Insulin tells the body cells, liver, muscle, and other organs to absorb glucose. The glucose can’t go into the cell without the permission of insulin. It behaves like Bose.
If insulin is not available in blood circulation, it may result in a high blood glucose level.
Are you at risk?
High blood glucose level –
If your body does not use insulin properly or the pancreas doesn’t produce enough insulin. Then your high blood glucose level leads to diabetes or hyperglycemia.
It may be due to genetic reasons. Suppose there is a mutation in glucose kinase. In that case, β-cell stops the secretion of insulin that results in hyperglycemia or high blood glucose level. It is usually known as MODY (Maturity Onset of Diabetic in Young).
MODY can be Type 1 or Type 2 diabetes. But if we concern with specific Type -2 diabetes, some risk factors can lead to type 2 diabetes –
- Being overweight,
- Fat distribution – if you have more fat storage in an abdomen, that increase risk of type 2 diabetes
- Sedentary lifestyle
A high blood sugar level can also lead to atherosclerosis which results in ischemic heart disease.
Low blood glucose level –
Too much secretion of insulin or lack of glucose in your body may develop Hypoglycaemia condition. Low blood glucose levels can be caused by –
- Certain medications like the oral hypoglycaemic agent, insulin injection, etc.
- Excessive alcohol consumption
- Excessive exercise
- Critical illness e.g., liver cirrhosis, fatty liver disease, sepsis, etc.
- Skipping or delay a meal
- Insulinoma (a type of tumor where an overproduction of insulin)
- Deficiency of glucagon hormone
The disruption of blood glucose level is not a disease, but it can indicate a health problem. You should change your lifestyle and do some physical exercise. It can be managed but can’t cure.
You should take proper medicine under the supervision of your physician.
You should keep your blood glucose level normal and maintain healthy body weight. Try to minimize refined/processed foods. You can follow the low and moderate glycaemic index diet.
Keep active and healthy!